Stern angle control for outboard motors



Aug. 12, 1969 P. F. THOENE STERN ANGLE CONTROL FOR OUTBOARD MOTORS 5 Sheets-Sheet 1 Filed Jan. 2, 1968 12; 1969 P. F. THOENE 3,460,505

STERN ANGLE CONTROL FOR OUTBOARD MOTORS 3 Sheets- Sheet 2 Filad Jan. 2'. 1968 Pm MN Aug. 12, 1969 P. F. THOENE I STERN ANGLE CONTROL FOR OUTBOARD MOTORS 3 Sheets-Sheet 5 Filad Jan. 2, 1968 United States Patent 3,460,505 STERN ANGLE CONTROL FOR OUTBOARD MOTORS Paul F. Thoene, 8648 New Hampshire St.,

Altton, Mo. 63123 Filed Jan. 2, 1968, Ser. No. 695,004 Int. Cl. B63h 21/26 US. Cl. 115-41 8 Claims ABSTRACT OF THE DISCLOSURE A control for outboard motors for varying the angle between the drive shaft housing of the motor and the transom of a boat. The control comprises a plunger slidable in a cylinder between a retracted and an extended position. The plunger is spring biased for rearward movement through a hole in the transom into abutting engagement with the drive shaft housing of the motor. A latch is provided for latching the plunger in either its retracted or extended position and a spring-biased shifting mechanism biases the latch in a shifting direction for unlatching of the plunger upon reduction of thrust of the motor.

Background of the invention This invention relates to a stern angle control for outboard motors, and more particularly to such a control which may 'be used with substantially all boats and motors.

It will be understood that in the propulsion of a boat by means of an outboard motor, or an inboard-outboard or stem drive motor, it is desirable for best performance that the axis of the propeller be maintained substantially horizontal irrespective of the attitude of the boat. Thus, as the velocity of the boat increases and the angle of the longitudinal axis of the boat to the surface of the water increases as the boat begins to plane on the surface of the water, the stern angle (the angle between the drive shaft of the motor and the transom of the boat) must be increased to maintain the motor drive shaft housing vertical and the axis of the propeller horizontal.

Several types of mechanisms have been developed and are commercially available for controlling the stern angle of the motor. Such mechanisms, however, generally utilize either an electric or hydraulic motor to swing the motor rearwardly against the thrust of the propeller. These devices are relatively expensive and difiicult to install, and are capable of being used only with particular types or classes of motors and particular types or classes of boats. The commercial acceptance of such stern angle controls, therefore, has been limited generally to the original equipment market where the control is designed specifically for a particular boat and motor combination. Although less complicated and expensive stern angle controls have been developed, these controls have not found widespread use due to their inability to adapt universally to all boat and motor combinations.

Summary of the invention Accordingly, among the several objects of the inven tion may be noted the provision of a stern angle control for outboard motors which may be utilized with substantially all boat and motor combinations; the provision of such a control which may be operated from within the boat while the boat is under way to change the stern angle of the motor according to the attitude of the boat; the provision of a control of the class described which utilizes the drag on the lower drive shaft housing of the motor to swing the motor away from the transom while the boat is under Way when the motor is decelerated to accomplish rearward swing of the motor, and which then utilizes the ice forward thrust of the propeller upon acceleration of the motor to accomplish forward swing of the motor; the provision of such a control including means for automatically latching the motor at a desired stern angle, the latching means being remotely controlled from within the boat and occuring automatically upon deceleration of the boat; and the provision of a control of the class described which is characterized by simplicity of construction, low cost and ease of installation and use.

Briefly, the present stern angle control is adapted for use with an outboard motor carried for pivotal swinging movement on the transom of a boat. The control comprises a tube adapted to be mounted on the transom of the boat, and a plunger slidable in the tube from a retracted position to an extended position. A spring is adapted to urge the plunger rearwardly through a hole in the transom for engagement of the rearward end of the plunger with the drive shaft housing of the motor. In addition, means are provided for latching the plunger in either its retracted or extended position. Other objects and features will be in part apparent and in part pointed out hereinafter.

Brief description of the drawings FIG. 1 is a side elevation of an outboard. motor mounted on the transom of a boat which incorporates the stern angle control of this invention, the motor being shown in an inward or minimum stern angle position;

FIG. 2 is a view similar to FIG. 1 showing the motor in an outward or maximum stern angle position;

FIGS. 3A and 3B are longitudinal sections of the control in its retracted and extended positions, respectively;

FIG. 4 is an exploded perspective of a portion of the control of FIG. 3; and

FIG. 5 is an end elevation of the control of FIG. 3A showing a means for operating or shifting the control.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Description of the preferred embodiment Referring now to the drawings, there is indicated at 1 in FIGS. 1 and 2 a boat having an outboard motor 3 mounted on its transom 5 for swinging movement on a generaly transverse horizontal axis so that the stern angle of the motor may be varied, and also for pivotal movement on a generally vertical axis for steering purposes. The motor 3 is conventional, comprising the usual drive shaft housing 7 having an engine (not shown) at its upper end enclosed in an engine housing 9. The propeller of the outboard motor is indicated at 11 and it will be understood that the propeller is driven from the engine via a drive shaft (not shown) extending down from the engine through the drive shaft housing 7.

Drive shaft housing 7 is pivotally mounted by means of a king pin (not shown) on a swivel bracket 13 for pivotal movement on a generally vertical axis for steering purposes. Swivel bracket 13 is mounted by means of a pin 15 on a transom bracket 17 for swinging movement on a generally transverse horizontal axis for varying the stern angle of the motor. Transom bracket 17, as will be understood, is clamped on transom 5 of the boat and is provided with a pair of transversely spaced arms 19 which straddle swivel bracket 13. Extending between these arms adjacent transom bracket 17 is a pin 21 received in holes in the arms. The forward side of swivel bracket 13 is engageable with this pin for establishing a minimum stern angle ofthe outboard motor in which the motor is generally vertical when the boat is level (FIG. 1). In accordance with this invention, a stern angle control 23 is mounted on transom 5 of the boat. Briefly, this control comprises a tube 25 having a plunger 27 slidable in its bore from a retracted position (FIG. 1) to an extended position (FIG. 2). The plunger 27 is spring biased rearwardly through a hole in the transom of the boat for abutting engagement of the rearward end 29 of the plunger with drive shaft housing 7 of the motor. Latching means 31 (FIGS. 3A and 3B) is provided for latching the plunger in either its retracted or extended position, and a pre-load shift mechanism 32 (FIG. is operable from within the boat to shift the latch.

The stern angle control 23 is illustrated in FIGS. 3A and 3B in its retracted and extended positions, respectively. The control is comprised of the tube 25 which is constituted by a cylinder having a peripheral circular flange 33 at its rearward end and an external screw thread 35 at its forward end. Cylinder 25 passes through a hole 37 in transom 5 of the boat and the flange 33 is apertured for passage of bolts 39 for securing the control to the transom. The plunger 27 is also a cylindric tube and is slidable in the bore of the cylinder 25. The rearward end 29 of plunger 27 has a hard rubber or plastic dome-shaped head 41 secured thereto, and the plunger is keyed against rotation by a stud 43 extending through cylinder 25 for engagement with a longitudinally extending slot 45 in the plunger.

Mounted in the forward end of cylinder 25 within the bore of plunger 27 is a tubular sleeve 47 having a flat end 49 and a head flange 51. The forward end of outer cylinder 25 is closed by an end cap 53 and the sleeve 47 is rotatably held in the bore of plunger 27 against longitudinal movement by thrust bearings 55 and 57 press fitted in outer cylinder 25 rearwardly and forwardly of the head flange 51. A similar thrust bearing 59 is fitted within the plunger 27 adjacent the end 49 of sleeve 47 and a coil compression spring 61 is disposed within plunger 27 between a thrust bearing 62 at its rearward end and the thrust bearing 59. A shaft 63 extends forwardly from flanged head 51 of sleeve 47 through an aperture in end cap 53 and is secured to a radially extending arm 65.

As best illustrated in FIGS. 3 and 4, the latch 31 for latching the plunger in either its retracted or extended position is comprised of a pair of diametrically opposed longitudinally extending double bayonet slots 67 in the sides of plunger 27, each of the slots having transverse circumferentially extending end portions 69 and 71. Riding in each of slots 67 is a latch pin constituted by a roller 73 journalled on an axle 75 secured to the opposite sides of sleeve 47. Thus, longitudinal sliding movement of plunger 27 is limited in a rearward direction by engagement of rollers 73 with the ends 71 of slots 67 (FIG. 3B), and in a forward direction by engagement of rollers 73 with the ends 69 (FIG. 3A).

As set forth above, sleeve 47 is held against longitudinal movement in the bore of plunger 27 but is rotatable about its longitudinal axis. The means for rotating sleeve 47 to move or rotate rollers 73 between their retracted plunger holding position in end portions 69 of the slots to their extended plunger holding position in end portions 71 of the slots is the pro-loaded shifting mechanism 32. This mechanism is illustrated in FIG. 5 as comprising a hand operable means or shift lever 77 pivotal on a shaft 79 in a shift block 81. The block 81 i mounted within the boat near the motor throttle control. The other end of the lever 77 is connected to a rod 83 of a push-pull control cable 85, the opposite end of which extends through a bushing 87 in an arm 89 fixed to end cap 53. The sheath of the cable terminates at the bushing 87 and the rod 83 extends through an aperture 91 in the end of arm 65. A pair of spaced flanged nuts 93 and 95 threadedly engage the rod and a pair of coil compression springs 97 and 99 are received on the rod between arm 65 and flanged nuts 93 and 95 for selectively biasing the arm to rotate in either direction. Stop pins 101 and 103 project from the face of end cap 53 for limiting pivotal motion of arm 65.

Operation is as follows:

Control 23 is installed on transom 5 of the boat such that the rearward end 29 of the control abuts the forward end of drive shaft housing 7 when the plunger is retracted and the motor is in the inward or minimum stern angle position of FIG. 1. Pin 21 on arms 19 of transom bracket 17 may be removed since the drive shaft housing abutting the control limits inward swing of the motor and establishes the minimum stern angle. Thus, the stern angle is such that the axis of propeller 11 is substantially horizontal. It will be understood that the boat remains in a level attitude, such as illustrated in FIG. 1, at low speeds but that it assumes a planing attitude, such as illustrated in FIG. 2, when the speed of the boat increases. If the stern angle remained fixed, the axis of the propeller would be inclined to the surface of the water. However, with the stern angle control of this invention, the axis of the propeller is maintained substantially parallel to the surface of the water, thereby increasing the efficiency, velocity and load carrying capacity of the boat.

With shift lever 77 in the in or minimum stern angle position, the outboard motor is started and the boat is accelerated in the usual manner. With lever 77 in this position, arm 65 is pivoted clockwise as viewed in FIG. 5 against stop 103 by movement of rod 83 to the right. This moves flanged nut 93 to the right compressing spring 97 and forcing arm 65 clockwise, as viewed from the FIG. 5 forward end of the control. The control in this position is illustrated in FIG. 3A. Thus, spring 61 is compressed and rollers 73 are seated in the rearward transverse end portions 69 of roller slots 67 and are biased to remain in these slots by the action of spring 97. As the throttle setting on the boat in increased and the boat accelerates, the thrust of the propeller maintains engagement of drive shaft housing 7 of the motor with rearward end 29 of the plunger. The plunger is held against forward movement under the thrust of the motor by engagement of the walls of slots 67 at their rearward ends 69 with rollers 73, the latter being afiixed to the longitudinally immovable sleeve 47. Thus, as the boat accelerates the motor is held against counterclockwise swinging movement as viewed in FIG. 1 by engagement of the drive shaft housing with the rearward end of the plunger.

When the boat begins to plane in a bow-up attitude, the motor is shifted to its outward or maximum stern angle position. This is accomplished by first shifting lever 77 to the out position and thereafter momentarily decreasing the motor throttle setting. When lever 77 is shifted to the out position, cable 83 forces flanged nut to the left as viewed in FIG. 5 thereby compressing spring 99 against the upper end of arm 65 to bias the arm in a counterclockwise direction toward stop 101. However, arm 65 does not rotate at this time because of the forcible engagement between rollers 73 and the rearward ends 69 of slots 67. That is, the thrust of the motor acting against plunger 27 is restrained by engagement of the rollers in the rearward end portions of the slots. This holds sleeve 47 against rotation under the urging of spring 99. Thus, the boat continues to plane with the plunger latched in its retracted position and with arm 65 against stop 103 but biased toward stop 101. To cause the motor to shift outwardly and increase the stern angle, the motor throttle setting is momentarily decreased to reduce the thrust of propeller 11. With the boat under way, this causes the motor to swing away from transom 5 due to the drag of the lower end of the drive shaft housing 7 with the water. When motor 3 swings away from the transom, the thrust of the motor pushing against the rearward end of plunger 27 terminates along with the forced engagement between rollers 73 and portions 69 of slots 67. Spring 99 then rotates arm 65 in a counterclockwise direction as viewed in FIG. 5 toward engagement with stop pin 101. This rotates sleeve 47 carrying rollers 73 until the axes of the rollers coincide with the longitudinal axes of slots 67. This unlatches or releases the plunger and permits it to move rearwardly under the influence of coil compression spring 61 until rollers 73 engage the forward ends of slots 67,

whereupon spring 99 causes the rollers to rotate into engagement with these end portions to latch the plunger in its extended or maximum stern angle position. The motor throttle setting is then increased causing the drive shaft housing 7 to again abut the rearward end of plunger 27. However, since the plunger is now extended rearwardly, the motor is held in its FIG. 2 outward position. The boat may now be operated in the usual manner. It should 'be noted that subsequent decreases or increases in the throttle setting, unaccompanied by subsequent movement of the shift lever 77, will not aflect the latch since spring 99 maintains rollers 73 in ends 69 of the slots.

When it is desired to slow or stop the boat the motor should be returned from its FIG. 2 outward position to its FIG. 1 inward position. To accomplish this, lever 77 is first shifted to the in position followed by decreasing and increasing the throttle setting of the motor. When lever 77 is shifted to this position, flanged nut 93 moves to the right as viewed in FIG. 5 compressing spring 97 and biasing arm 65 toward stop 103. Again, however, this arm does not rotate because the thrust of the motor maintains forcible engagement between rollers 73 and forward end portions 71 of slots 67. After lever 77 has been shifted, the motor throttle setting is decreased to reduce the thrust of the motor pushing against plunger 27 and to release engagement of the rollers with the end portions 71 of the slots. As soon as this occurs, spring 97 forces arm 65 toward stop 103 and rotates sleeve 47 until the axes of the rollers is again in line with the longitudinal axes of the slots. The motor throttle setting is then increased again to permit the thrust of the motor to cock or force the plunger 27 inwardly against the bias of spring 61 until the rearward ends of the slots engage the rollers. Spring 97 then forces these rollers into the transverse end portions 69 of the slots to latch the plunger in its rearward position. The throttle may then be adjusted to either stop the boat or to permit operation at reduced velocity. It should be noted that in shifting the roller and slot latch mechanism, the throttle need only be decreased momentarily. This may be accomplished simply by retarding the throttle and immediately advancing it to its initial position. It should also be noted that a simple pin or stud may be used for the latch pin in place of rollers 73.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above con structions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A stern angle control for an outboard motor carried for pivotal swinging movement on the transom of a boat, said control comprising a tube adapted to be mounted on the transom of the boat, a plunger slidable in said tube from a retracted position to an extended position, a spring adapted to urge said plunger rearwardly through a hole in the transom for engagement of the rearward end of the plunger with the drive shaft housing of the motor, means for latching said plunger in either its retracted or extended position, said latching means comprising a latch pin engageable with said plunger for holding said plunger in either of its positions against the thrust of the motor, and means for moving said latch pin between a retracted plunger holding position and an extended holding position, said means being operable to move said latch pin only during reduced thrust intervals of operation of the motor.

2. A control as set forth in claim 1 wherein said means for moving said latc'h pin is biased to move this pin upon reduction of the thrust of the motor to permit the plunger to be moved in the cylinder from one of its positions to the other.

3. A control as set forth in claim 2 wherein said means for moving said latch pin includes hand operable means for selectively biasing said latch pin toward either its retracted or extended plunger holding position.

4. A control as set forth in claim 1 wherein said tube is a cylinder, and said plunger is biased for abutting engagement with the drive shaft housing of the motor, said latching means comprising an elongate slot extending 1ongitudinally in the side of the plunger, said slot having transversely extending end portions, and a. latch pin riding in said slot, said latch pin being held against longitudinal movement in said cylinder.

5. A control as set forth in claim 4 wherein said latch pin is mounted for limited rotation in said cylinder.

6. A control as set forth in claim 5 including means for rotating said latch pin, said means comprising an arm secured to said latch pin, a coil compression spring on each side of said arm, and a control for selectively compressing either of said springs against said arm to bias the latch pin to rotate when the thrust of the motor is reduced.

7. A control as set forth in claim 6 wherein said latch pin is a roller journalled on an axle secured to a cylindric sleeve carried by the cylinder within the bore of the plunger.

8. A stern angle control for an outboard motor carried on the transom of a boat for pivotal swinging movement about a generally horizontal axis, said control comprising a cylinder having a flange at its; rearward end, said flange being adapted to be secured to the transom of the boat, a plunger slidable in said cylinder from a retracted position to an extended position, a coil compression spring urging said plunger rearwardly in said cylinder through a hole in the transom for abutting engagement of the rearward end of the plunger with the drive shaft housing of the motor, a latch for holding said plunger in either of its positions, said latch comprising an elongate slot extending longitudinally in the side of the plunger, said slot having transversely extending end portions, and a latch pin riding in said slot, said latch pin being secured to a rotatable sleeve carried in said cylinder, said sleeve being held against longitudinal movement in said cylinder, and means for moving said latch pin to permit longitudinal movement of said plunger, said means comprising an arm fixed to said sleeve, a pair of springs on opposite sides of said arm, and a shift lever having a control cable connected to said springs for selectively compressing either of said springs against said arm to bias said sleeve and latch pin for rotation in said cylinder when the thrust of the motor is reduced.

References Cited UNITED STATES PATENTS 2,901,194 8/1959 Shontz -41 2,927,552 3/1960 Mickey 115-41 3,039,724 6/1962 Herreman 115-41 X TRYGVE M. BLIX, Primary Examiner US. Cl. X.R. 115-17; 248-4 

